EP1962115A2 - Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument - Google Patents

Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument Download PDF

Info

Publication number
EP1962115A2
EP1962115A2 EP08005191A EP08005191A EP1962115A2 EP 1962115 A2 EP1962115 A2 EP 1962115A2 EP 08005191 A EP08005191 A EP 08005191A EP 08005191 A EP08005191 A EP 08005191A EP 1962115 A2 EP1962115 A2 EP 1962115A2
Authority
EP
European Patent Office
Prior art keywords
refractive index
laminated portion
index layers
laminated
layers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP08005191A
Other languages
English (en)
French (fr)
Other versions
EP1962115A3 (de
EP1962115A9 (de
Inventor
Yorio Wada
Ken Kawamata
Nobuyoshi Toyohara
Yoshiki Shinta
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Olympus Corp
Original Assignee
Olympus Corp
Olympus Medical Systems Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2003299226A external-priority patent/JP4331547B2/ja
Priority claimed from JP2003299224A external-priority patent/JP4468667B2/ja
Priority claimed from JP2003299225A external-priority patent/JP4343620B2/ja
Priority claimed from JP2003354027A external-priority patent/JP4409244B2/ja
Application filed by Olympus Corp, Olympus Medical Systems Corp filed Critical Olympus Corp
Publication of EP1962115A2 publication Critical patent/EP1962115A2/de
Publication of EP1962115A3 publication Critical patent/EP1962115A3/de
Publication of EP1962115A9 publication Critical patent/EP1962115A9/de
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B21/00—Microscopes
    • G02B21/16—Microscopes adapted for ultraviolet illumination ; Fluorescence microscopes
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/208—Filters for use with infrared or ultraviolet radiation, e.g. for separating visible light from infrared and/or ultraviolet radiation
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/22—Absorbing filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/22—Absorbing filters
    • G02B5/223—Absorbing filters containing organic substances, e.g. dyes, inks or pigments
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters
    • G02B5/285—Interference filters comprising deposited thin solid films

Definitions

  • the present invention relates to an optical filter and optical instrument.
  • a fluorescence microscope which is an optical instrument used when observing biological specimens, is able to analyze the structure and nature of a specimen, such as a cell that has been treated with dye, by observing fluorescent light emitted by the specimen when excitation light is irradiated thereon.
  • a minus filter which is an optical filter that cuts out light in a predetermined wavelength band and allows light of other wavelengths to pass through in this manner, is manufactured, as is shown in FIG. 33A , using a multi-layer film in which layers having a high refractive index and layers having a low refractive index are laminated alternatingly on a substrate.
  • the horizontal axis shows the optical thickness while the vertical axis shows the film refractive index.
  • FIG 33B the relationship between the transmittance and the wavelength of light that passes through a film during construction of the film is shown as a spectral characteristic.
  • the optical thickness is determined by multiplying the physical thickness of the film by the index of the film.
  • the optical filter is able to make the rise at boundaries between transmission bands and stopbands sharper as the number of the aforementioned layers is increased.
  • the problem arises that as the number of layers is increased, the ripples in the transmission bands also increase.
  • FIG 34A it is possible to design a film in which ripples are reduced by changing the optical thickness of each layer, however, as is shown in FIG 34B , it is difficult to do away with ripples completely.
  • FIG. 35A if the refractive index of the film is changed cyclically and continuously in the optical thickness direction such that the refractive index distribution thereof is formed into what is known as a "wavelet" configuration, then, as is shown in FIG. 35B , it is possible to fundamentally do away with ripples in the transmission band.
  • FIG. 36A, FIG. 36B , FIG. 37A, FIG. 37A , FIG. 38A, and FIG. 38A various types of structures have been proposed in which a continuous refractive index distribution is divided into stages and approximated.
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to this first laminated portion, and a third laminated portion that adjacent to this second laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers becomes gradually higher approaching the substrate, in the second laminated portion, the refractive indices of the high refractive index layers are substantially equal to the highest refractive index of the high refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive indices of the high refractive index layers become gradually lower from the second laminated portion side, and the refractive indices of the low refractive index layers are substantially
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to this first laminated portion, a third laminated portion that is adjacent to this second laminated portion, and a fourth laminated portion that is adjacent to this third laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers becomes gradually higher approaching the substrate, and the refractive indices of the low refractive index layers become gradually lower approaching the substrate, in the second laminated portion, the refractive indices of the high refractive index layers become gradually higher from the highest refractive index of the high refractive index layers constituting the first laminated portion, and the refractive indices of the low ref
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to the first laminated portion, and a third laminated portion that is adjacent to the second laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers becomes gradually higher approaching the substrate, in the second laminated portion, the refractive indices of the high refractive index layers are substantially equal to the highest refractive index of the high refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive indices of the high refractive index layers become gradually lower from the second laminated portion side, and wherein the refractive indices of the low refractive index
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to the first laminated portion, and a third laminated portion that is adjacent to the second laminated portion, and wherein in the first laminated portion, the refractive indices of the low refractive index layers become gradually lower approaching the substrate side, in the second laminated portion, the refractive indices of the low refractive index layers are substantially equal to the lowest refractive index of the low refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive indices of the low refractive index layers become gradually higher from the second laminated portion side, and wherein the refractive indices of the high refractive
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is provided with laminated portions having predetermined refractive index profiles, and wherein the refractive index profiles are formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the refractive index profiles are represented by a first laminated portion, a second laminated portion that is laminated on the substrate side of the first laminated portion, and a third laminated portion that is laminated on the substrate side of the second laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers become gradually higher approaching the substrate side, in the second laminated portion, the refractive indices of the high refractive index layers are substantially equal to the highest refractive index of the high refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is provided with laminated portions having predetermined refractive index profiles, and wherein the refractive index profiles are formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the refractive index profiles are represented by a first laminated portion and a second laminated portion that is adjacent to the substrate side of the first laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers become gradually higher approaching the substrate side, and the refractive indices of the low refractive index layers become gradually lower approaching the substrate side, and in the second laminated portion, the refractive indices of the high refractive index layers become gradually lower approaching the substrate side, and the refractive indices of the low refractive index layers become gradually higher approaching the substrate side, and wherein an optical
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is provided with laminated portions having a first refractive index profile and a second refractive index profile, and wherein the first and second refractive index profiles are formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the first refractive index profile and the second refractive index profile are continuous, and wherein each of the first refractive index profile and the second refractive index profile is represented by a first laminated portion, a second laminated portion that is laminated on the substrate side of the first laminated portion, and a third laminated portion that is laminated on the substrate side of the second laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers become gradually higher approaching the substrate side, in the second laminated portion, the refractive indices of the
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is provided with laminated portions having a first refractive index profile and a second refractive index profile, and wherein the first and second refractive index profiles are formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the first refractive index profile and the second refractive index profile are continuous, and wherein each of the first refractive index profile and the second refractive index profile is represented by a first laminated portion and a second laminated portion that is adjacent to the substrate side of the first laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers become gradually higher approaching the substrate side, and the refractive indices of the low refractive index layers become gradually lower approaching the substrate side, in the second laminated portion, the refractive indices of
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to the first laminated portion, and a third laminated portion that is adjacent to the second laminated portion, and wherein in the first laminated portion, the refractive indices of the high refractive index layers become gradually higher approaching the substrate, in the second laminated portion, the refractive indices of the high refractive index layers are substantially equal to the highest refractive index of the high refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive indices of the high refractive index layers become gradually lower from the second laminated portion side, and wherein lamination patterns in which the first laminated portion, the second laminate
  • the present invention is an optical filter formed by a substrate and a thin film that is formed on the substrate, wherein the thin film is formed by laminating low refractive index layers whose refractive index is relatively low alternatingly from the substrate side with high refractive index layers whose refractive index is relatively high, and wherein the thin film is provided with a first laminated portion, a second laminated portion that is adjacent to the first laminated portion, and a third laminated portion that is adjacent to the second laminated portion, and wherein in the first laminated portion, the refractive indices of the low refractive index layers become gradually lower approaching the substrate, in the second laminated portion, the refractive indices of the low refractive index layers are substantially equal to the lowest refractive index of the low refractive index layers constituting the first laminated portion, and in the third laminated portion, the refractive indices of the low refractive index layers become gradually higher from the second laminated portion side, and wherein lamination patterns in which the first laminated portion, the second laminate
  • the present invention is an optical filter provided with a substrate and a thin film that is formed on the substrate, wherein the thin film has an outermost layer portion that is in contact with an optical medium whose refractive index is lower than the refractive index of the substrate, and has laminated portions having predetermined refractive profiles, and wherein the refractive index profiles are formed by laminating low refractive index layers alternatingly with high refractive index layers approaching the substrate side, and wherein the refractive indices of the low refractive index layers is higher than the refractive index of the optical medium, and the refractive indices of the high refractive index layers is relatively higher than the refractive index of the low refractive index layers, and wherein the outermost layer portion is provided with an outermost low refractive index layer, a first outermost high refractive index layer that is laminated on the outermost low refractive index layer, and a second outermost high refractive index layer that is laminated on the first outermost high refractive index layer, and wherein the
  • FIGS. 1 , 2A, and 2B Next, the first embodiment of the present invention will be described with reference made to FIGS. 1 , 2A, and 2B .
  • the optical instrument according to the present embodiment is shown in FIG 1 .
  • the optical instrument in FIG 1 is a fluorescence microscope.
  • the fluorescence microscope 10 is provided with an excitation filter 11, a dichroic mirror 12, an absorption filter (i.e., an optical filter) 13, an ocular lens 14, and an objective lens 15.
  • the excitation filter 11 is placed on an optical path of the light source 16. As a result of this placement, it selectively allows only specific wavelengths out of the light that is generated from the light source 16 to pass through in the form of excitation light.
  • the dichroic mirror 12 is placed on the opposite side from the light source 16 sandwiching the excitation filter 11 so as to bend the optical axis at an angle of 45°. Accordingly, excitation light that has passed through the excitation filter 11 is irradiated via the objective lens 15 onto a specimen 17 such as, for example, a biological cell. As a result of this irradiation fluorescent light is generated from the specimen 17. Because the generated fluorescent light has a different wavelength from that of the excitation light, it passes through the dichroic mirror 12 and arrives at the observing side.
  • the ocular lens 14 and objective lens 15 form an observation optical system. Using this observation optical system, an image of the aforementioned fluorescent light can be observed.
  • the absorption filter 13 is formed by a glass substrate 18, a thin film 19, and an incident medium 18'.
  • the thin film 19 is formed on top of the substrate 18.
  • the incident medium 18' is provided on top of the thin film 19.
  • This absorption filter 13 has optical characteristics that selectively allow only the aforementioned fluorescent light to pass through.
  • the incident medium 18' is formed by a member (for example, a glass plate) having the same refractive index as that of the substrate 18.
  • the absorption filter 13 will now be described.
  • the absorption filter is shown by the symbol 13-1.
  • the thin film 19 is formed by low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 have a relatively high refractive index in comparison with the refractive indices of the low refractive index layers 20.
  • the low refractive index layers 20 and the high refractive index layers 21 are laminated alternatingly from the substrate 18 side.
  • the thin film 19 is also formed by a first laminated portion 22, a second laminated portion 23, and the third laminated portion 24. From the substrate 18 side towards the incident medium 18', the laminated portions are laminated in order of the third laminated portion 24, the second laminated portion 23, and the first laminated portion 22. In addition, each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18. Furthermore, in the first laminated portion 22, the refractive indices of the low refractive index layers 20 are substantially uniform. In this case, the low refractive index layers 20 have a low refractive index layer fixed portion.
  • the second laminated portion 23 is adjacent to the first laminated portion 22.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of the high refractive index layers 21 are substantially the same as the highest refractive index of the high refractive index layers 21 constituting the first laminated portion 22.
  • the refractive indices of the low refractive index layers 20 are substantially uniform at first. Thereafter, from partway along the refractive indices become gradually lower. Then, once again, the refractive indices become substantially uniform at the end.
  • the second laminated portion 23 has a low refractive index layer fixed portion 26 where the refractive indices are at first substantially uniform, and a low refractive index layer decreasing portion 25 where the refractive indices become gradually lower.
  • Low refractive index layer fixed portions 26 are provided on both sides of the low refractive index layer decreasing portion 25. Note that portions of a low refractive index layer fixed portion 26 also form the low refractive index layers 20 of the first laminated portion 22.
  • the third laminated portion 24 is adjacent to the second laminated portion 23.
  • the refractive indices of the high refractive index layers 21 become gradually lower from the second laminated portion 23 side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same as the lowest refractive index of the low refractive index layers 20 constituting the second laminated portion 23.
  • the low refractive index layers 20 are mainly formed from silicon oxide.
  • the high refractive index layers 21 are mainly formed from niobium oxide.
  • the refractive index of the substrate 18 is set to 1.8.
  • the refractive indices of the high refractive index layers 21 change from 1.81 to 2.2.
  • the refractive indices of the low refractive index layers 20 change from 2.0 to 1.8 in the low refractive index layer decreasing portion 25.
  • a central wavelength of a wavelength band in which transmission is blocked is taken as ⁇ .
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set at one quarter of the design wavelength.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are each 150 nm.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 68.
  • a substrate having a refractive index of 2.0 is also provided on the incident medium 18' side of the thin film 19.
  • the results of a simulation with these parameters and conditions are shown in FIG. 2B .
  • This excitation light is reflected by the dichroic mirror 12 and is irradiated onto the objective lens 15.
  • the excitation light is then condensed by the objective lens 15 and is irradiated onto the specimen 17.
  • fluorescent light is generated from the specimen 17 by this irradiation.
  • This fluorescent light is formed into parallel light via the objective lens 15. This parallel light arrives at the dichroic mirror 12, passes through the dichroic mirror 12, and arrives at the absorption filter 13.
  • the fluorescent light that reaches the absorption filter 13 i.e., the filter 13-1 in FIG. 2A
  • the fluorescent light then passes through the second laminated portion 23 and the third laminated portion 24 and is once again emitted to the outside from the substrate 18 side.
  • Reflected light which includes excitation light in addition to fluorescent light, that is reflected from the specimen 17 is reflected by the dichroic mirror 12. However, a portion passes through the dichroic mirror 12. As a result, excitation light is also irradiated onto the absorption filter 13.
  • the thin film 19 is provided with the above described first laminated portion 22 through the third laminated portion 24. Therefore, it is possible to provide the absorption filter 13 with the spectral transmittance characteristics shown in FIG 2B .
  • the absorption filter 13-1 is manufactured such that the wavelength band to which the excitation light and the like belongs is matched to the stopband 28, while the wavelength band to which the fluorescent light belongs is matched to the transmission bands. If this type of structure is employed, it is possible to allow fluorescent light only to pass through while preventing excitation light from passing through.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set to one quarter of the design wavelength. If this type of structure is employed, then control of the optical thickness during film formation is simplified. As a result, a uniform optical thickness can be consistently formed. Accordingly, it is possible to improve the optical characteristics of the obtained thin film.
  • Fluorescent light that is emitted from the absorption filter 13 in this manner is irradiated onto the ocular lens 14. This fluorescent light passes through the ocular lens 14 and is condensed and then arrives at the observation side.
  • the second embodiment differs from the first embodiment in the following point. Namely, in a thin film 40 according to the second embodiment a low refractive index layer decreasing portion 25 is provided at a distal end side of the first laminated portion 22.
  • the second embodiment also differs in that the refractive indices of the low refractive index layers of the second laminated portion 23 are substantially uniform.
  • the absorption filter 13-2 is provided with the thin film 40.
  • a low refractive index layer decreasing portion 25 is provided in the low refractive index layers 20 of the first laminated portion 22.
  • a low refractive index layer fixed portion 26 is provided moving from the low refractive index layer decreasing portion 25 towards the substrate 18 side in the low refractive index layers 20 that constitute the first and second laminated portions 22 and 23.
  • a refractive index variation layer portion is provided in the thin film 40.
  • a layer 41 is present here that is lower than the high refractive index layers 21 on both sides thereof. Because this layer 41 is on the high refractive index side, here, it is taken as a high refractive index variation layer portion 41.
  • This high refractive index variation layer portion 41 is provided on the first laminated portion 22 side.
  • a high refractive index variation layer portion 41 is also provided in the vicinity of the boundary between the second laminated portion 23 and the third laminated portion 24.
  • This high refractive index variation layer portion 41 is provided on the third laminated portion 24 side. Note that the high refractive index variation layer portions 41 are adjacent to the high refractive index layers 21 on both sides thereof via low refractive index layers 20.
  • Low refractive index variation layer portions are also provided in the low refractive index layers 20. If the vicinity of the boundary between the first laminated portion 22 and the second laminated portion 23 is observed, it can be seen that a layer 42 is present here in which the refractive index of the low refractive index layer 20 is higher than that of the low refractive index layers 20 on both sides thereof. This is a low refractive index variation layer portion 42. This low refractive index variation layer portion 42 is provided on the first laminated portion 22 side. In the same way, a low refractive index variation layer portion 42 is also provided in the vicinity of the boundary between the second laminated portion 23 and the third laminated portion 24. This low refractive index variation layer portion 42 is provided on the third laminated portion 24 side.
  • the refractive indices of the high refractive index layer 21 in the second laminated portion 23 are 2.2.
  • the refractive indices of the high refractive index variation layer portions 41 are set to 2.15.
  • the refractive indices of the low refractive index layers 20 in the second laminated portion 23 are set to 1.4.
  • the refractive indices of the low refractive index variation layer portions 42 are set to 1.42.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 75.
  • the thin film 40 is inserted between an incident medium 18' having a refractive index of 1.8 and a substrate 18 having a refractive index of 1.4.
  • the results of a simulation with these parameters and conditions are shown in FIG. 3B .
  • the absorption filter 13-2 of the present embodiment as is shown, for example, in FIG. 3B , by altering the position of the low refractive index layer decreasing portion 25, it is possible to alter the width of the stopband 28. Furthermore, because both the high refractive index variation layer portion 41 and the low refractive index variation layer portion 42 are provided, it is possible to suppress ripples even further. Accordingly, in the same way as in the first embodiment, it is possible to reduce ripples 29a in the transmission bands of fluorescent light and to consistently obtain a sufficient quantity of light.
  • the absorption filter 13-3 of the third embodiment is provided with a thin film 50.
  • the thin film 50 is formed by a first laminated portion 51, a second laminated portion 52, a third laminated portion 53, and a fourth laminated portion 54. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the fourth laminated portion 54, the third laminated portion 53, the second laminated portion 52, and the first laminated portion 51.
  • each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18.
  • the refractive indices of the low refractive index layers 20 become gradually lower approaching the substrate 18.
  • the second laminated portion 52 is adjacent to the first laminated portion 51.
  • the refractive indices of the high refractive index layers 21 become gradually higher from the first laminated portion S side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform. The refractive indices of these low refractive index layers 20 are substantially the same as the lowest refractive index of the low refractive index layers 20 constituting the first laminated portion 51.
  • the third laminated portion 53 is adjacent to the second laminated portion 52.
  • the refractive indices of the high refractive index layers 21 become gradually lower from the second laminated portion 52 side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the refractive indices of these low refractive index layers 20 are substantially the same as the lowest refractive index of the low refractive index layers 20 constituting the first laminated portion 51.
  • the fourth laminated portion 54 is adjacent to the third laminated portion 53.
  • the refractive indices of the high refractive index layers 21 become gradually lower from the third laminated portion 53 side.
  • the refractive indices of the low refractive index layers 20 become gradually higher from the third laminated portion 53 side.
  • the refractive index of the substrate 18 is set to 1.8.
  • the refractive indices of the high refractive index layers 21 change from 1.81 to 2.2.
  • the refractive indices of the low refractive index layers 20 change from 1.4 to 1.8.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 45.
  • a substrate having a refractive index of 1.8 is also inserted on the incident medium 18' side of the thin film 32.
  • the results of a simulation with these parameters and conditions are shown in FIG. 4B .
  • the absorption filter 13-3 of the present embodiment as is shown, for example, in FIG 4B , it is possible to suppress ripples 29a in the same way as in the other embodiments. Furthermore, because the refractive indices of the low refractive index layers 20 constituting the second and third laminated portions 52 and 53 are substantially uniform, control of the refractive indices during film formation is a simple matter.
  • the absorption filter 13-4 is provided with a thin film 60.
  • the thin film 60 is formed by a first laminated portion 22, a second laminated portion 23, and a third laminated portion 24. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the third laminated portion 24, the second laminated portion 23, and the first laminated portion 22. In addition, each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the second laminated portion 23 is adjacent to the first laminated portion 22.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of the high refractive index layers 21 are substantially the same as the highest refractive index of the high refractive index layers 21 constituting the first laminated portion 22.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the third laminated portion 24 is adjacent to the second laminated portion 23.
  • the refractive indices of the high refractive index layers 21 become gradually lower from the second laminated portion 23 side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 constituting the first through third laminated portions 22 to 24 are substantially uniform.
  • the absolute value of the gradient of the refractive index in the first laminated portion 22 is smaller than the absolute value of the gradient of the refractive index in the third laminated portion.
  • the area where the absolute value of the gradient of the refractive index is small is broader in comparison with the area in which the absolute value of the gradient of the refractive index is large.
  • a thin film 60 is formed that provides this type of refractive index gradient.
  • the refractive index of the substrate 18 is set to 1.5.
  • the refractive indices of the high refractive index layers 21 change from 1.55 to 2.4.
  • the refractive indices of the low refractive index layers 20 are a uniform value of 1.5.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 63.
  • a substrate having a refractive index of 1.5 is also inserted on the incident medium 18' side of the thin film 60.
  • the results of a simulation with these parameters and conditions are shown in FIG 5B .
  • control of the refractive index during film formation is more difficult than control of the optical thickness. Accordingly, if there are irregularities in the refractive indices of the refractive index layers, it is difficult to obtain the desired optical performance.
  • the refractive index gradients of the high refractive index layers 21 are set such that the absolute value of the refractive index gradient in the first laminated portion 22 is smaller than the absolute value of the refractive index gradient in the third laminated portion, then even if irregularities occur in the refractive index layer in the first laminated portion 22, the effects thereof can be reduced. Accordingly, even if the refractive index varies during film formation, the film structure has little deterioration in the optical performance (such as ripples or blunting of the sharpness of the rise in the spectral characteristics).
  • the absorption filter 13-5 of the fifth embodiment is provided with a thin film 70.
  • the absorption filter 13-5 differs from that of the fourth embodiment in the following points. Namely, in the thin film 70 according to the fifth embodiment, the gradients of the refractive indices of the high refractive index layers 21 are formed such that the absolute value of the gradient of the refractive indices of the high refractive index layers 21 in the first laminated portion 22 is larger than the absolute value of the gradient of the refractive indices of the high refractive index layers 21 in the third laminated portion 24.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 63.
  • a substrate having a refractive index of 1.5 is also inserted on the incident medium 18' side of the thin film 70.
  • the results of a simulation with these parameters and conditions are shown in FIG 6B .
  • the thin film 70 of the present embodiment has the same operation and effects as the thin film 60 of the fourth embodiment.
  • the absorption filter 13-6 of the sixth embodiment is provided with a thin film 80.
  • the thin film 80 is formed by a first laminated portion 22, a second laminated portion 23, and a third laminated portion 24. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the third laminated portion 24, the second laminated portion 23, and the first laminated portion 22. In addition, each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 become gradually lower approaching the substrate 18.
  • the second laminated portion 23 is adjacent to the first laminated portion 22.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same as the lowest refractive index of the low refractive index layers 20 constituting the first laminated portion 22.
  • the third laminated portion 24 is adjacent to the second laminated portion 23.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 become gradually higher from the second laminated portion 23 side.
  • the refractive index of the substrate 18 is set to 1.8.
  • the refractive indices of the high refractive index layers 21 is a uniform value of 1.8.
  • the refractive indices of the low refractive index layers 20 change from 1.4 to 1.75.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 45.
  • a substrate having a refractive index of 1.8 is also inserted on the incident medium 18' side of the thin film 70.
  • the results of a simulation with these parameters and conditions are shown in FIG 7B .
  • the absorption filter 13-6 of the present embodiment as is shown, for example, in FIG. 7B , in the same way as in the above described embodiments, it is possible to suppress ripples in the transmission bands and consistently obtain a sufficient quantity of light. Moreover, because the refractive indices of the high refractive index layers 21 are uniform, control of the refractive indices during film formation is a simple matter.
  • the design wavelength is set to 600 nm, which is the same as the central wavelength, and the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set to one quarter of the design wavelength.
  • n 2
  • the design wavelength is set to 600/n (wherein n is an integer) nm.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set to n/4 of the design wavelength. Even if a thin film is formed with the optical thicknesses set in this manner, it is possible to obtain an optical filter having exactly the same spectral characteristics.
  • the filter 13 of the seventh through eleventh embodiments differs from those of the above described embodiments in the following point. Namely, in the above described embodiments, the optical thicknesses of the low refractive index layers 20 and the high refractive index layers 21 are the same, however, in the present embodiment these optical thicknesses are different.
  • the absorption filter 13-7 of the seventh embodiment is provided with a thin film 200. As is shown in FIG. 8A , in the thin film 200, low refractive index layers 20 whose refractive indices are relatively low and high refractive index layers 21 whose refractive indices are relatively high are laminated alternatingly from the substrate 18 side.
  • a refractive index profile P is represented by a first laminated portion 22' , a second laminated portion 23', and a third laminated portion 24'.
  • the thin film 200 is formed by these three laminated portions. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the third laminated portion 24', the second laminated portion 23', and the first laminated portion 22'. In addition, each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the third laminated portion 24' is laminated on the substrate 18 side of the first laminated portion 22'.
  • the refractive indices of the high refractive index layers 21 become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the second laminated portion 23' is laminated between the first laminated portion 22' and the third laminated portion 24'.
  • the refractive indices of the high refractive index layers 21 are substantially uniform.
  • the refractive indices of these high refractive index layers 21 are substantially the same as the highest refractive index from among the high refractive index layers 21 1 constituting the first laminated portion 22'.
  • the refractive indices of the low refractive index layers 20 are substantially uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same in each of the first laminated portion 22', the second laminated portion 23', and the third laminated portion 24'. Moreover, the optical thickness of the high refractive index layers 21 and the optical thickness of the low refractive index layers 20 are different from each other. In addition, the refractive indices of the low refractive index layers 20 are substantially the same as the refractive index of the substrate 18.
  • the low refractive index layers 20 are mainly formed from silicon oxide.
  • the high refractive index layers 21 are mainly formed from niobium oxide.
  • the refractive index of the substrate 18 and the low refractive index layers 20 are set to 1.5.
  • the refractive indices of the high refractive index layers 21 are changed between 1.5 and 2.4.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers of the thin film 200 is set at 47. This total number of layers is the number of layers from the substrate 18 side to the final layer that is adjacent to the incident side medium 18'.
  • the design wavelength is 600 nm.
  • the optical thicknesses of the high refractive index layers 21 are 0.25 times the design wavelength, while the optical thicknesses of the low refractive index layers 20 are 0.5 times the design wavelength.
  • This absorption layer 13-7 is provided with a stopband 22A, a stopband 22B, a transmission band 23A, and a transmission band 23B.
  • a central wavelength where transmission is obstructed is 450 nm, and the bandwidth where transmittance is 0% is approximately 40 nm.
  • a central wavelength where transmission is obstructed is 920 nm, and the bandwidth where transmittance is 0% is approximately 160 nm.
  • the transmission band 23A and the transmission band 23B are provided with bandwidths that allow wavelengths other than these to be transmitted.
  • this absorption filter 13-7 As is shown, for example, in FIG 8B , it is possible to form sharp boundaries between the stopbands 22A and 22B and the transmission bands 23A and 23B. As a result, it is possible to increase the amount of transmitted light in the transmission bands 23A and 23B. Furthermore, in addition to these effects, it is possible to suppress ripples.
  • the optical thickness ratio between the high refractive index layers 21 and the low refractive index layers 20 is set to 1:2 without changing the refractive index in each layer of the refractive index profile P.
  • a stopband 22B in a wavelength band having 920 nm as the central wavelength. Accordingly, out of the incident light that it is irradiated into the absorption filter, it is possible to prevent the transmission of light in the wavelength bands 22A and 22B, whose central wavelength is 450 nm and 920 nm, and to allow the transmission of light in the transmission bands 23A and 23B. Therefore, fluorescent dyes are selected that are excited by the light of the wavelength bands 22A and 22B to generate fluorescent light in the transmission bands 23A and 23B.
  • this type of structure it is possible to make an observation with little loss of fluorescent light, and it is possible to make considerable improvements in the detection sensitivity when measuring fluorescent light. As a result, for example, in genome analysis and the like, it is possible to improve analysis accuracy and detection accuracy, and to shorten the observation time.
  • the refractive indices of the low refractive index layers 20 are set to the same value as the refractive index of the substrate 18. Accordingly, it is possible to suppress loss at boundaries between the substrate 18 and the thin film 200, and to further improve the amount of light transmitted in the transmission bands 23A and 23B.
  • the eighth embodiment differs from the seventh embodiment in the following point. Namely, in the seventh embodiment, the refractive indices of the low refractive index layers 20 are the same as that of the substrate 18, however, in the eighth embodiment the refractive indices of the low refractive index layers 20 are gradually changed.
  • the absorption filter 13-8 of the present embodiment is provided with a thin film 210.
  • the refractive index profile 27 of the thin film 210 is represented by a first laminated portion 31 and a second laminated portion 30.
  • the thin film 210 is formed by these two laminated portions. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the second laminated portion 30 and the first laminated portion 31. In addition, each laminated portion has low refractive index layers 20 and high refractive index layers 21.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 become gradually lower approaching the substrate 18 side.
  • the second laminated portion 30 is adjacent to the first laminated portion 31 on the substrate 18 side thereof.
  • the refractive indices of the high refractive index layers 21 become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 become gradually higher approaching the substrate 18 side.
  • the optical thickness of the high refractive index layers 21 and the optical thickness of the low refractive index layers 20 are different from each other.
  • the refractive index of the substrate 18 is set to 1.8.
  • the refractive indices of the low refractive index layers 20 change between less than 1.80 and 1.4.
  • the refractive indices of the high refractive index layers 21 change between 1.82 and 2.2.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers of the thin film 210 is set at 45.
  • the design wavelength is 800 nm.
  • the optical thicknesses of the high refractive index ' layers 21 are 0.25 times the design wavelength, while the optical thicknesses of the low refractive index layers 20 are 0.125 times the design wavelength.
  • This absorption layer 13-8 is provided with a stopband 33A, a transmission band 35A, and a transmission band 35B.
  • the central wavelength is 610 nm
  • the bandwidth where transmittance is 0% is approximately 60 nm.
  • the transmission bands 35A and 35B are provided with bandwidths that allow wavelengths other than these to be transmitted.
  • the absorption filter 13-8 as is shown, for example, in FIG 9B , in the same way as in the seventh embodiment, it is possible to reduce ripples in the transmission bands of fluorescent light. Accordingly, when making an observation of fluorescent light, it is possible to consistently obtain a sufficient quantity of fluorescent light.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set at a ratio of 2:1. As a result, compared with when the optical thicknesses of the two are the same (i.e. as is the case conventionally), it is possible to narrow the bandwidth in the stopband 33B where transmittance is 0%.
  • a bandwidth of approximately 150 nm in a conventional stopband to a bandwidth of approximately 60 nm.
  • the ratio of the optical thicknesses it is possible to change the ratio of the optical thicknesses. For example, it is possible to set the optical thicknesses of the high refractive index layers 21 to 0.125 times the design wavelength, and to set the optical thicknesses of the low refractive index layers 20 to 0.25 times the design wavelength. In this case, the optical thickness ratio becomes 1:2, which is the reverse to that shown in FIG 9A .
  • FIG 10B it is still possible to form a stopband 33A that is the same as that shown in FIG. 9B .
  • the central wavelength and the bandwidth of the stopband 33A are substantially the same as those shown in FIG 9B . In this way, it is possible to obtain the same operation and effects as those described above even if the ratio of the optical thicknesses is changed.
  • the total number of layers of the thin film is changed.
  • a case in which the total number of layers of the thin film is 100 and the design wavelength is 1200 nm is shown in FIG. 11A .
  • the optical thicknesses of the high refractive index layers 21 are 0.025 times the design wavelength, while the optical thicknesses of the low refractive index layers 20 are 0.5 times the design wavelength. Accordingly, the optical thickness ratio is 1:20.
  • the spectral transmittance characteristics of the absorption filter 13-8" are as is shown in FIG. 11B .
  • the stopband 43B it is possible to contract a bandwidth where transmittance is 0% from a conventional approximately 80 nm to approximately 10 nm.
  • FIG. 12A Another example in which the ratio of the optical thicknesses has been changed is shown in FIG. 12A .
  • the optical thicknesses of the high refractive index layers 21 are 0.025 times the design wavelength, while the optical thicknesses of the low refractive index layers 20 are 1.0 times the design wavelength.
  • the optical thickness ratio is 1:40.
  • the spectral transmittance characteristics of the absorption filter 13-8'" are as is shown in FIG 12B .
  • the stopband 48A it is possible to contract a bandwidth where transmittance is 0% from a conventional approximately 30 nm to approximately 5 nm.
  • stopbands can be set in a plurality of wavelength bands.
  • the absorption filter 13-9 of the ninth embodiment is provided with a thin film 220.
  • the ninth embodiment differs from the above described embodiments in the following points. Namely, in the ninth embodiment, the thin film 220 is provided with a first refractive index profile P1 and a second refractive index profile P2. In addition, a laminated portion having the first refractive index profile P1 and a laminated portion having the second refractive index profile P2 are laminated consecutively.
  • the first refractive index profile P1 is represented by a first laminated portion 56 and a second laminated portion 58.
  • the second refractive index profile P2 is represented by a first laminated portion 61 and a second laminated portion 63.
  • the thin film 220 is formed by these four laminated portions. From the substrate 18 side towards the incident medium 18', the laminated portions are, formed in order of the second laminated portion 63, the first laminated portion 61, the second laminated portion 58,and the first laminated portion 56. In addition, each laminated portion has low refractive index layers and high refractive index layers.
  • the first refractive index profile P 1 will now be described.
  • the refractive indices of the high refractive index layers 55A become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 55B become gradually lower approaching the substrate 18 side.
  • the second laminated portion 58 is adjacent to the first laminated portion 56 on the substrate 18 side thereof.
  • the refractive indices of the high refractive index layers 57A become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 57B become gradually higher approaching the substrate 18 side.
  • the first laminated portion 61 is adjacent to the second laminated portion 58 on the substrate 18 side thereof.
  • the refractive indices of the high refractive index layers 60A become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 60B become gradually lower approaching the substrate 18 side.
  • the second laminated portion 63 is laminated on the substrate 18 side of the first laminated portion 61.
  • the refractive indices of the high refractive index layers 62A become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 62B become gradually higher approaching the substrate 18 side.
  • At least one refractive index variation portion has a optical thickness that is different from that of the others.
  • the refractive index of the substrate 18 is set to 1.9.
  • the refractive indices of the high refractive index layers 55A, 57A, 60A, and 62A are changed between 1.9 and 2.2.
  • the refractive indices of the low refractive index layers 55B, 57B, 60B, and 62B are changed between less than 1.9 and 1.6.
  • the laminated portion having the first refractive index profile P1 and the laminated portion having the second refractive index profile P2 each have a total of 80 laminated layers. Accordingly, in the thin film 220 as a whole, the total number of laminated layers is 160.
  • the design wavelength is 1500 nm.
  • the optical thicknesses of the high refractive index layers 55A and 57A and of the Tow refractive index layers 55B and 57B are each set to 0.25 times the design wavelength.
  • the optical thicknesses of the high refractive index layers 60A and 62A and of the low refractive index layers 60B and 62B are each set to 0.5 times the design wavelength.
  • This absorption filter 13-9 is provided with a stopband 65A, a stopband 65B, a stopband 65C, and transmission bands 66A, 66B, 66C, and 66D.
  • a central wavelength where transmission is obstructed is 500 nm, and the bandwidth where transmittance is 0% is approximately 20 nm.
  • a central wavelength where transmission is obstructed is 430 nm, and the bandwidth where transmittance is 0% is approximately 10 nm.
  • the stopband 65C a central wavelength where transmission is obstructed is 600 nm, and the bandwidth where transmittance is 0% is approximately 10 nm.
  • the transmission bands 66A, 66B, 66C, and 66D are provided with bandwidths that allow wavelengths other than these to be transmitted.
  • the absorption filter 13-9 of the present embodiment it is possible to form sharp boundaries between the stopbands 65A, 65B, and 65C, and the transmission bands 66A, 66B, 66C, and 66D, which are bands excluding these stopbands. Therefore, for example, even if the wavelength band of the fluorescent light is close to the wavelength of the excitation light, the excitation light and fluorescent light can be excellently separated. As a result, it is possible to increase the amount of fluorescent light that is transmitted. In addition, it is possible to more effectively suppress ripples in the transmission bands. Moreover, three stopbands 65A, 65B, and 65C can be set using a single absorption filter 13-9.
  • the absorption filter 13-10 of the tenth embodiment is provided with a thin film 230.
  • the tenth embodiment differs from the ninth embodiment in the following points. Namely, in the tenth embodiment, the refractive index maximum value in the high refractive index layers of the first refractive index profile P 1 is different from the refractive index maximum value in the high refractive index layers of the second refractive index profile P2. In addition, the refractive index minimum value in the first refractive index profile P 1 is different from the refractive index minimum value in the second refractive index profile P2.
  • the refractive index of the substrate 18 is set to 1.9.
  • the refractive indices of the high refractive index layers 71A and 72A are changed between 1.9 to 2.1.
  • the refractive indices of the low refractive index layers 71B and 72B are changed between less than 1.9 to 1.7.
  • the refractive indices of the high refractive index layers 73A and 74A are changed between 1.9 to 2.2.
  • the refractive indices of the low refractive index layers 73B and 74B are changed between less than 1.9 to 1.6.
  • This absorption filter 13-10 has the same spectral characteristics as the absorption filter 13-9 according to the ninth embodiment. Namely, the absorption filter 13-10 is provided with a stopband 76A, a stopband 76B, a stopband 76C, and transmission bands 77Aa, 77B, 77C, and 77D.
  • the central wavelength is 500 nm.
  • the central wavelength is 430 nm.
  • the central wavelength is 600 nm.
  • the transmission bands 77A, 77B, 77C, and 77D allow light of wavelengths other than these to pass through.
  • the bandwidth where the transmittance is 0% in the stopband 76A is 5 nm.
  • the bandwidth of the stopband 76A is narrower than that of the stopband 65A of the absorption filter 13 according to the ninth embodiment.
  • the same operation and effects as those from the absorption filter 13-9 of the ninth embodiment can be obtained.
  • the width of the stopbands can be optionally changed.
  • FIG. 15A An example of this is shown in FIG. 15A .
  • the optical thicknesses of the low refractive index layers 80B and 81B are altered. Specifically, the optical thicknesses of the low refractive index layers 80B and 81 Bare altered from 0.5 times the design wavelength to 0.25 times the design wavelength.
  • the spectral transmittance characteristics of the absorption filter 13-10' in this case are shown in FIG. 15B .
  • the absorption filter 13-10' shown in FIG 15A in comparison with FIG 14A , it is possible to move the central wavelength of the stopband 83B from 430 nm to 450 nm. In addition to this, it is possible to move the central wavelength of the stopband 83C from 600 nm to 570 nm.
  • FIG. 16A shows another example.
  • the optical thicknesses of the low refractive index layers 86B and 87B are 0.05 times the design wavelength.
  • the spectral transmittance characteristics of the absorption filter 13-10" in this case are shown in FIG. 16B .
  • the absorption filter 13-10' shown in FIG. 16A in comparison with FIG 14A , it is possible to move the central wavelength of the stopband 90B from 430 nm to 420 nm.
  • a new stopband 90D can be formed in which the central wavelength is 830 nm, and the bandwidth where the transmittance is 0% is approximately 10 nm.
  • the same operation and effects as in the above described embodiments can be obtained.
  • the positions of the stopbands can be set to optional positions.
  • the absorption filter 13-11 of the eleventh embodiment is provided with a thin film 240.
  • the eleventh embodiment differs from the tenth embodiment in the following points. Namely, in the thin film 240 of the absorption filter 13-11 according to the eleventh embodiment, the refractive indices of the low refractive index layers are substantially the same as the refractive index of the substrate.
  • the thin film 240 is provided with a first refractive index profile P 1 and a second refractive index profile P2.
  • a laminated portion having the first refractive index profile P1 and a laminated portion having the second refractive index profile P2 are laminated consecutively.
  • the first refractive index profile P1 is represented by a first laminated portion 96, a second laminated portion 97, and a third laminated portion 98.
  • the second laminated portion 97 is laminated between the first laminated portion 96 and the third laminated portion 98.
  • the second refractive index profile P2 is represented by a first laminated portion 103, a second laminated portion 105, and a third laminated portion 106.
  • the second laminated portion 105 is laminated between the first laminated portion 103 and the third laminated portion 106.
  • the thin film 240 is formed by these six laminated portions. From the substrate 18 side towards the incident medium 18', the laminated portions are formed in order of the third laminated portion 106, the second laminated portion 105, the first laminated portion 103, the third laminated portion 98, the second laminated portion 97,and the first laminated portion 96. In addition, each laminated portion has low refractive index layers and high refractive index layers.
  • the first refractive index profile P will now be described.
  • the refractive indices of the high refractive index layers 101 become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 111 are uniform.
  • the refractive indices of the high refractive index layers 102 become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 111 are uniform.
  • the refractive indices of the high refractive index layers 100 are uniform.
  • the refractive indices of the high refractive index layers 100 are substantially the same as the highest refractive index of the high refractive index layers 101 of the first laminated portion 96. Note that the refractive indices of the high refractive index layers 100 are substantially the same as the highest refractive index of the high refractive index layers 102 of the third laminated portion 98.
  • the second refractive index profile P2 will now be described.
  • the refractive indices of the high refractive index layers 108 become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 112 are uniform.
  • the refractive indices of the high refractive index layers 110 become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 112 are uniform.
  • the second laminated portion 105 - the refractive indices of the high refractive index layers 107 are uniform.
  • the refractive indices of the high refractive index layers 107 are substantially the same as the highest refractive index of the high refractive index layers 108 of the first laminated portion 103. Note that the refractive indices of the high refractive index layers 107 are substantially the same as the highest refractive index of the high refractive index layers 110 of the third laminated portion 106.
  • the refractive indices of the low refractive index layers 111 in the first refractive index profile P 1 and the refractive indices of the low refractive index layers 112 in the second refractive index profile P2 are substantially the same as the refractive index of the substrate 18.
  • the refractive index of the substrate 18 and the refractive indices of the low refractive index layers 111 and 112 are set to 1.5.
  • the refractive indices of the high refractive index layers 101 and 102 are changed between 1.55 and 2.2.
  • the refractive indices of the high refractive index layers 100 are set to 2.2.
  • the refractive indices of the high refractive index layers 108 and 110 are changed between 1.55 and 2.4.
  • the refractive indices of the high refractive index layers 107 are set to 2.4.
  • the total number of the laminated sections having the first refractive index profile P 1 and the laminated sections having the second refractive index profile P2 is 97. Moreover, the design wavelength is 600 nm. In the first refractive index profile P1, the optical thicknesses of the high refractive index layers 100, 101, and 102 and of the low refractive index layers 111 are each 0.25 times the design wavelength. In contrast, in the second refractive index profile P2, the optical thicknesses of the high refractive index layers 107, 108, and 110 are each 0.25 times the design wavelength, while the optical thicknesses of the low refractive index layers 112 are 0.5 times the design wavelength.
  • This absorption filter 13-11 is provided with a stopband 113A, a stopband 113B, and transmission bands 115A, 115B, and 115C.
  • the central wavelength is 600 nm and the bandwidth where transmittance is 0% is approximately 120 nm.
  • the central wavelength is 450 nm and the bandwidth where transmittance is 0% is approximately 40 nm.
  • the transmission bands 115A, 115B, and 115C are provided with bandwidths that allow wavelengths other than these to pass through.
  • the same operation and effects as in the above described embodiments can be obtained.
  • the positions of the stopbands can be set to optional positions.
  • the width of the stopbands can be adjusted to an optional width.
  • the absorption filter 13-12 of the present embodiment is provided with a thin film 400.
  • this thin film 400 is formed by a laminated portion having a first refractive index profile P1 and a laminated portion having a second refractive index profile P2.
  • Each laminated portion has low refractive index layers and high refractive index layers. These low refractive index layers and high refractive index layers are laminated alternatingly.
  • the first refractive index profile P1 is represented by a first laminated portion 300, a second laminated portion 310, and a third laminated portion 320. These three laminated portions are laminated from the substrate 18 side in order of the third laminated portion 320, the second laminated portion 310, and the first laminated portion 300.
  • the refractive index distributions of each laminated portion are as is described below.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18.
  • the refractive indices of the low refractive index layers 20 become gradually lower approaching the substrate 18.
  • the second laminated portion 310 is adjacent to the first laminated portion 300.
  • the refractive indices of the high refractive index layers 21 are uniform.
  • the refractive indices of these high refractive index layers 21 are substantially the same as the highest refractive index of the high refractive index layers 21 that constitute the first laminated portion 300.
  • the refractive indices of the low refractive index layers 20 are uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same as the lowest refractive index of the first laminated portion 300.
  • the third laminated portion 320 is adjacent to the second laminated portion 310.
  • the refractive indices of the high refractive index layers 21 become gradually lower from the second laminated portion 310 side.
  • the refractive indices of the low refractive index layers 20 become gradually higher from the second laminated portion 310.
  • the second refractive index profile P2 has the same profile as that of the first refractive index profile P 1.
  • the second refractive index profile P2 is represented by a fourth laminated portion 330, a fifth laminated portion 340, and a sixth laminated portion 350. These three laminated portions are laminated from the substrate 18 side in order of the sixth laminated portion 350, the fifth laminated portion 340, and the fourth laminated portion 330.
  • the fourth laminated portion 330 has the same refractive index distribution as that of the first laminated portion 300.
  • the fifth laminated portion 340 has the same refractive index distribution as that of the second laminated portion 310.
  • the sixth laminated portion 350 has the same refractive index distribution as that of the third laminated portion 320.
  • the low refractive index layers 20 are mainly formed from magnesium fluoride, while the high refractive index layers 21 are mainly formed from niobium oxide.
  • the refractive index of the substrate 18 is set to 1.8.
  • the refractive indices of the high refractive index layers 21 are changed from 1.9 to 2.2.
  • the refractive indices of the low refractive index layers 20 are changed from 1.4 to 1.75.
  • This thin film 400 has refractive index variation layer portions. For example, if the vicinity of the boundary between the first laminated portion 330 and the second laminated portion 310 is observed, it can be seen that a layer 360 is present here that is lower than the high refractive index layers 21 on both sides thereof. Because this layer 360 is on the high refractive index side, here, it is taken as a high refractive index variation layer portion 360. This high refractive index variation layer portion 360 is provided on the first laminated portion 330 side.
  • a high refractive index variation layer portion 360 is also provided in the vicinity of the boundary between the second laminated portion 310 and the third laminated portion 320.
  • This high refractive index variation layer portion 360 is provided on the third laminated portion 320 side.
  • the refractive indices of the high refractive index layers 21 and the second laminated portion 310 are 2.2.
  • the refractive index of the high refractive index variation layer portions 360 are set to 2.1.
  • the central wavelengths of the wavelength bands where transmission is blocked are taken as ⁇ 1 and ⁇ 2.
  • the design wavelength is taken as ⁇ 1/n, ⁇ 2/m (wherein n and mare integers).
  • the design wavelength become respectively A 1 and A 2.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 in each refractive index profile are each set at one quarter of the design wavelength.
  • a 1 is set to 600 nm and ⁇ 2 is set to 720 nm. Accordingly, the respective optical thicknesses are 150 nm and 180 nm.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 89.
  • a substrate having a refractive index of 1.8 is also provided on the incident medium 18' side of the thin film 400.
  • FIG. 18B transmission bands 390 are formed on both sides of a stopband 380.
  • the stopband 380 is the waveband to which, for example, excitation light and the like belongs.
  • the transmission bands 390 are wavebands to which fluorescent light belongs. Accordingly, in these wavebands, fluorescent light is allowed to pass through to the observation side.
  • this absorption filter 13-12 for example, as is shown in FIG 18B , it is possible to widen the stopband 380. This is because the refractive index distribution is the same and also because a plurality of lamination patterns of different optical thicknesses are employed. Moreover, the first refractive index profile P and the second refractive index profile P2 only have different optical thicknesses from each other, and the refractive index distributions of the respective refractive index profiles are the same. Consequently, the film structure allows control to be simplified during film formation. As a result, it is possible to improve the consistency of the optical characteristics.
  • the absorption filter 13-13 of the thirteenth embodiment differs from that of the twelfth embodiment in the following points. Namely, in that the wavelength ⁇ 1 in the first refractive index profile P1 is 480 nm, and in that the optical thickness thereof is 120 nm.
  • the total number of laminated layers of the thin film 410 is 89.
  • a substrate having a refractive index of 1.8 is also provided on the incident medium 18' side of the thin film 410. In this simulation, there is also no refractive index dispersion in each layer. The results of a simulation with these parameters and conditions are shown in FIG. 19B .
  • a stopband 380A is formed by the first refractive index profile P1 and a stopband 380B is formed by the second refractive index profile P2. At this time, the stopband 380A and the stopband 380B are formed in separated positions. Accordingly, it is possible to obtain filter characteristics having a transmission region 390 between the two.
  • the absorption filter 13-14 of the fourteenth embodiment differs from that of the twelfth embodiment in the following points. Namely, in the thin film 420 of the fourteenth embodiment, the refractive indices of the low refractive index layers 20 are uniformly set to the same value as the refractive index of the substrate 18. This is the same in both the first refractive index profile P 1 and the second refractive index profile P2.
  • the absorption filter 13-14 also differs in that there are no refractive index variation layer portions 360.
  • the thin film 420 is formed by first through sixth laminated portions 300 to 350, however, the refractive indices of the low refractive index layers 20 that constitute each laminated portion are set to the same value as the refractive index of the substrate 18.
  • the refractive index of the substrate 18 is set to 1.5.
  • the refractive indices of the high refractive index layers 21 are changed from 1.55 to 2.4.
  • the refractive indices of the low refractive index layers 20 are set to a uniform value of 1.5.
  • the results are shown when a simulation was performed for spectral transmittance of the absorption filter.
  • the total number of laminated layers is set at 93.
  • a substrate having a refractive index of 1.5 is also provided on the incident medium 18' side of the thin film 420.
  • the results of a simulation with these parameters and conditions are shown in FIG. 20B .
  • the absorption filter of the present embodiment as well, for example as is shown in FIG 20B , it is possible to obtain a wide stopband 380 in the same way as in the above described first embodiment. Namely, it is possible to obtain filter characteristics in which the stopband of the first refractive index profile P1 and the stopband of the second refractive index profile P2 are combined.
  • the design wavelength is the same as the central wavelength in each lamination pattern.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set to one quarter of the design wavelength.
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set to one half of the design wavelength. It is possible to obtain a spectral filter having exactly the same spectral characteristics even if a thin film is formed under these conditions.
  • n is an integer
  • the optical thicknesses of the high refractive index layers 21 and the low refractive index layers 20 are set at n/4 of the design wavelength. Even when a thin film is formed under these conditions, it is still possible to obtain an absorption filter having exactly the same spectral characteristics.
  • the absorption filter 13-15 is formed by a glass substrate 18, and by a thin film 500 that is formed on top of the substrate 18. This absorption filter 13-15 differs from the absorption filters previously described in that there is no incident side medium 18'. Due to this structure, the absorption filter 13-15 of the present embodiment selectively allows only the above described fluorescent light to pass through.
  • the thin film 500 is formed by an outermost layer portion 600 and a portion having a refractive index profile 610.
  • the portion having the refractive index profile 610 has low refractive index layers and high refractive index layers. In the portion having the refractive index profile 610, these low refractive index layers and high refractive index layers are laminated alternatingly.
  • the outermost layer portion 600 is in contact with air (i.e., an optical medium) 18" whose refractive index is lower than that of the substrate 18.
  • the refractive indices of the low refractive index layers 20 of the portion having the refractive index profile 610 are higher than the refractive index of the air 18" and equal to or lower than the refractive index of the substrate 18.
  • the refractive indices of the high refractive index layers 21 of the portion having the refractive index profile 610 are relatively higher than the refractive indices of the low refractive index layers 20.
  • This outermost layer 600 will now be described. As is described above, the outermost layer portion 600 is in contact with the air 18".
  • This outermost layer 600 has an outermost low refractive index layer 600A, a first outermost high refractive index layer 600B, and a second outermost high refractive index layer 600C.
  • the refractive index is set to be higher than the refractive index of air and equal to or lower than the refractive index of the substrate.
  • the first outermost high refractive index layer 600B is laminated onto the outermost low refractive index layer 600A. In the first outermost high refractive index layer 600B, the refractive index is set to be higher than the refractive index of the outermost low refractive index layer 600A.
  • the second outermost high refractive index layer 600C is laminated onto the first high refractive index layer 600B. In the second outermost high refractive index layer 600C, the refractive index is set to be higher than the refractive index of the first outermost high refractive index layer 600B.
  • the refractive index profile P is represented by a first laminated portion 610A, a second laminated portion 610B, and a third laminated portion 610C.
  • the first laminated portion 610A is laminated on the substrate 18 side of the outermost layer portion 600.
  • low refractive index layers 20 are adjacent to the outermost layer portion 600.
  • high refractive index layers 21 are adjacent to the outermost layer portion 600.
  • the refractive indices of the high refractive index layers 21 are higher than the refractive index of the second outermost high refractive index layer 600C.
  • the refractive indices of the high refractive index layers 21 become gradually higher approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 are uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same as the refractive index of the outermost low refractive index layer 600A.
  • the third laminated portion 610C is laminated on the substrate 18 side of the first laminated portion 610A.
  • the refractive indices of the high refractive index layers 21 become gradually lower approaching the substrate 18 side.
  • the refractive indices of the low refractive index layers 20 become gradually higher approaching the substrate 18 side. Note that the refractive indices of the low refractive index layers 20 ultimately become substantially the same as the refractive index of the substrate 18.
  • the second laminated portion 610B is laminated between the first laminated portion 610A and the third laminated portion 610C.
  • the refractive indices of the high refractive index layers 21 are uniform.
  • the refractive indices of the high refractive index layers 21 are substantially the same as the highest refractive index of the high refractive index layers 21 in the first laminated portion 610A.
  • the refractive indices of the low refractive index layers 20 are uniform.
  • the refractive indices of the low refractive index layers 20 are substantially the same as the refractive index of the outermost low refractive index layer 600A.
  • the low refractive index layers 20 are mainly formed from magnesium fluoride, while the high refractive index layers 21 are mainly formed from tantalum oxide.
  • the refractive index of the substrate 18 is set to 1.52.
  • the refractive index of the outermost low refractive index layer 600A in the outermost layer portion 600 is set to 1.4, while the refractive indices of the first outermost high refractive index layer 600B and the second outermost high refractive index layer 600C of the outermost layer portion 600 are set respectively to 1.5 and 1.6.
  • the refractive indices of the high refractive index layers 21 are changed from 1.7 to 2.2.
  • the refractive indices of the high refractive index layers 21 are changed from 1.52 to 2.2.
  • the refractive indices of the low refractive index layers 20 are set to 1.4.
  • the refractive indices of the low refractive index layers 20 are changed from 1.4 to less than 1.52.
  • the total number of laminated layers is 45. This number is the total number from the substrate 18 side to the outermost low refractive index layer 600A of the outermost layer portion 600.
  • the design wavelength is 600 nm.
  • the optical thickness of each layer is 0.25 times the design wavelength.
  • This absorption filter 13-15 is provided with a stopband 700 and transmission bands 710A and 710B.
  • the central wavelength where transmission is obstructed is approximately 610 nm.
  • the bandwidth where transmittance is approximately 0% is approximately 140 nm.
  • the transmission bands 710A and 710B allow wavelengths other than these to be transmitted.
  • this absorption filter 13-15 for example, as is shown in FIG. 21B , it is possible to form sharp boundaries between the stopband 700 and transmission bands 710A and 710B. As a result, the amount of light transmitted in the transmission bands 710A and 710B can be increased. Furthermore, it is possible to suppress the generation of ripples in the vicinity of the boundaries. Moreover, because the film structure simplifies control of the optical thickness during film formation, it is possible to improve the consistency of the optical characteristics.
  • the absorption filter 13-15 has optical characteristics that are close to those of an ideal filter. Therefore, if this absorption filter 13-15 is used in the fluorescence microscope 10, the detection sensitivity when measuring fluorescent light can be improved considerably. Namely, in a conventional filter, the transmittance is reduced in wavelength regions that are close to excitation light from among the wavelength regions of fluorescent light. As a result, in the conventional filter, the amount of transmitted fluorescent light is reduced. However, in the filter of the present embodiment, it is possible to transmit the amount of light of these wavelength regions (i.e., the increased portion of the amount of light) at a high transmittance.
  • the refractive indices of the low refractive index layers 20 are laminated as they change. Accordingly, it is possible to suppress loss at boundaries between the substrate 18 and the thin film 500. As a result, it is possible to further improve the amount of light transmitted in the transmission bands 710A and 710B.
  • the absorption filter may also be formed like the absorption filter 13-15' shown in FIG. 23A .
  • the refractive index profile of the thin film 511 is changed: Specifically, in the first laminated portion 611 A, the total number of laminated layers is increased from 12 to 28. As a result, the rate of change of the high refractive index layers 21 is a more gently sloping rate of change than that of the first laminated portion 610A shown in FIG. 21A .
  • FIG 23B it is possible to obtain substantially the same spectral transmittance characteristics as those shown in FIG. 21B even when this type of structure is employed. Namely, it is possible to form a stopband 701 that is provided with the same central wavelength and bandwidth as that shown in FIG.
  • FIG 24A and FIG 24B are comparative examples.
  • the outermost layer portion 601 is not provided.
  • ripples are generated in the vicinity of the boundaries.
  • the absorption filter shown in FIG. 23A the same operation and effects as those shown in FIG. 21A can be obtained.
  • the absorption filter may also be formed like the absorption filter 13-15" shown in FIG. 25A .
  • a different refractive index profile P is formed.
  • the total number of laminated layers of the first laminated portion 612A is decreased from 12 to 4.
  • the rate of change of the high refractive index layers 21 is a more abruptly sloping rate of change than that of the first laminated portion 610A shown in FIG. 21A .
  • FIG. 26A and FIG. 26B are comparative examples in which the outermost layer portion 602 is not provided. In this comparative example as well, ripples are generated in the vicinity of the boundaries. Compared with the case shown in FIG. 26A , in the absorption filter shown in FIG. 25A , the same operation and effects as those shown in FIG. 21A can be obtained.
  • the sixteenth embodiment differs from the fifteenth embodiment in the following points. Namely, in the fifteenth embodiment, there is only one refractive index profile in the substrate 18, however, in the sixteenth embodiment there are two refractive index profiles in the substrate 18. Specifically, as a refractive index profile P, the thin film 510 of the absorption filter 13-16 is provided with a first refractive index profile P 1 and a second refractive index profile P2. In addition, laminated portions having these profiles are laminated adjacent to each other in sequence approaching the substrate 18 side.
  • a laminated portion having the second refractive index profile P2 is laminated on the substrate 18.
  • a laminated portion having the first refractive index profile P 1 is then laminated on top of that, and an outermost layer portion 600 is then further laminated on top of that.
  • each layer in the outermost layer portion 600 and the optical thicknesses of each layer in the first refractive index profile P 1 are different from the optical thicknesses of each layer in the second refractive index profile P2.
  • the term “each layer in the first refractive index profile P1" refers to the high refractive index layers 21 and the low refractive index layers 20.
  • the term “each layer in the second refractive index profile P2" refers to the high refractive index layers 21' and the low refractive index layers 20'.
  • the refractive index of the substrate 18 is 1.52, which is the same as in the fifteenth embodiment.
  • the first refractive index profile P1 is represented by a first laminated portion 620A, a second laminated portion 620B, and a third laminated portion 620C.
  • the first refractive index profile P1 is the same as the refractive index profile P in the fifteenth embodiment.
  • the refractive indices of the first laminated portion 620A, the second laminated portion 620B, and the third laminated portion 620C are the same as those of the first laminated portion 610A, the second laminated portion 610B, and the third laminated portion 610C.
  • the second refractive index profile P2 is represented by a first laminated portion 630A, a second laminated portion 630B, and a third laminated portion 630C.
  • the refractive indices of the low refractive index layers 20' change between less than 1.52 and 1.4.
  • the refractive indices of the low refractive index layers 20' are set to 1.4.
  • the refractive indices of the high refractive index layers 21' are changed between 1.52 and 2.2.
  • the total number of laminated layers is 89. This number is the total number from the substrate 18 to the outermost low refractive index layer 600A of the outermost layer portion 600.
  • the design wavelength is 600 nm.
  • the optical thicknesses of each layer in the first refractive index profile P1 are 0.25 times the design wavelength.
  • the optical thicknesses of each layer in the second refractive index profile P2 are 0.3 times the design wavelength.
  • This absorption filter 13-16 is provided with a stopband 720 and transmission bands 730A and 730B.
  • the central wavelength where transmission is obstructed is substantially 680 nm.
  • the bandwidth where transmittance is substantially 0% is approximately 280 nm.
  • the transmission bands 730A and 730B allow light of wavelengths other than these to pass through.
  • FIG 28A and FIG. 28B show a case in which the outermost layer portion 600 is not provided.
  • the absorption filter 13-16 of the present embodiment in the same way as in the first embodiment, it is possible to reduce ripples in the fluorescent light transmission bands 730A and 730B.
  • this absorption filter 13-16 it is possible to consistently obtain a sufficient amount of light.
  • the position of the central wavelength of the stopband 720 can be moved to an optional position.
  • the width of the stopband 720 can be set to an optional size.
  • the seventeenth embodiment differs from the fifteenth embodiment in the following point. Namely, in that, in the absorption filter 13-17 of the seventeenth embodiment, the refractive indices of each layer of an outermost layer portion 640 of a thin film 520 and of each layer in a refractive index profile P are different from those in the fifteenth embodiment.
  • the refractive index of the outermost low refractive index layer 640A is set to 1.46
  • the refractive index of the first outermost high refractive index layer 640B is set to 1.56
  • the refractive index of the second outermost high refractive index layer 640C is set to 1.66.
  • a first laminated portion 650A the refractive indices of the high refractive index layers 21 are changed from 1.76 to 2.29.
  • a third laminated portion 650C the refractive indices of the high refractive index layers 21 are changed from 1.52 to 2.29.
  • the refractive indices of the low refractive index layers 20 are set to 1.46.
  • the refractive indices of the low refractive index layers 20 are changed between 1.46 and less than 1.52.
  • the total number of laminated layers is 44. This number is the total number of layers from the substrate 18 side to the outermost low refractive index layer 640A of the outermost layer portion 640.
  • the design wavelength is 600 nm.
  • the optical thicknesses of each layer are 0.25 times the design wavelength.
  • the low refractive index layers 20 are mainly formed from silicon oxide, while the high refractive index layers 21 are mainly formed from titanium oxide.
  • This absorption filter 13-17 is provided with a stopband 740 and transmission bands 750A and 750B.
  • the central wavelength where transmission is obstructed is substantially 610 nm.
  • the bandwidth where transmittance is substantially 0% is approximately 140 nm.
  • the transmission bands 750A and 750B allow light of wavelengths other than these to pass through.
  • FIG. 30A and FIG. 30B show a case in which the outermost layer portion 640 is not provided.
  • this absorption filter 13-17 As can be seen in a comparison with FIG. 30A , according to this absorption filter 13-17, the same operation and effects as those obtained in the first embodiment can be obtained when the refractive indices of each layer are different from the refractive indices in the fifteenth embodiment. Namely, according to this absorption filter 13-17 as well, it is possible to reduce ripples in the transmission bands 750A and 750B.
  • the degree of freedom in the film formation process can be increased.
  • the eighteenth embodiment differs from the seventeenth embodiment in the following point. Namely, as is shown in FIG. 31A , in the thin film 530 of the absorption filter 13-18 of the eighteenth embodiment, the outermost layer portion 660 is not in contact with air 13, but is in contact with glass (i.e., an optical medium) 18"' having a refractive index of 1.46.
  • the difference with the refractive index of the glass 18"' is clearly evident. Therefore, in an outermost low refractive index layer 660A and in a first laminated portion 670A and second laminated portion 670B, the refractive indices of the low refractive index layers 20 are set to 1.67. In addition, in a third laminated portion 670C, the refractive indices of the low refractive index layers 20 are changed between 1.67 and 2.29.
  • the refractive index of a first outermost high refractive index layer 660B is set to 1.72
  • the refractive index of a second outermost high refractive index layer 660C is set to 1.8
  • the refractive indices of the high refractive index layers 21 are changed between 1.8 and 2.29.
  • the total number of laminated layers is 44. This number is the total number of layers from the substrate 18 side to the outermost low refractive index layer 660A of the outermost layer portion 660.
  • the design wavelength is 600 nm.
  • the optical thicknesses of each layer are 0.25 times the design wavelength.
  • the outermost low refractive index layer 660A and the low refractive index layers 20 are mainly formed from alumina.
  • This absorption filter 13-18 is provided with a stopband 760 and transmission bands 770A and 770B.
  • the central wavelength is substantially 610 nm.
  • the bandwidth where transmittance is substantially 0% is approximately 90 nm.
  • the transmission bands 770A and 770B allow light of wavelengths other than these to pass through.
  • FIG. 32A and FIG 32B show a case in which the outermost layer portion 660 is not provided.
  • the same operation and effects as those obtained in the seventeenth embodiment can be obtained even if the outermost layer portion 660 is in contact with an optical medium other than air such as the glass 18"'.
  • the central wavelength ( ⁇ ) is not limited to 600 nm, and by appropriately changing the value of A in accordance with the wavelength of the excitation light and the wavelength of the fluorescent light to be detected, it is possible to obtain the desired spectral characteristics.
  • the material of the substrate is not limited to glass, and plastic may also be used.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Optical Filters (AREA)
EP08005191A 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument Withdrawn EP1962115A3 (de)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
JP2003299226A JP4331547B2 (ja) 2003-08-22 2003-08-22 光学フィルタ及び光学機器
JP2003299224A JP4468667B2 (ja) 2003-08-22 2003-08-22 光学フィルタ及び光学機器
JP2003299225A JP4343620B2 (ja) 2003-08-22 2003-08-22 光学フィルタ及び光学機器
JP2003354027A JP4409244B2 (ja) 2003-10-14 2003-10-14 光学フィルタ及び光学機器
EP04019510A EP1508822B1 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
EP04019510A Division EP1508822B1 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument

Publications (3)

Publication Number Publication Date
EP1962115A2 true EP1962115A2 (de) 2008-08-27
EP1962115A3 EP1962115A3 (de) 2008-09-03
EP1962115A9 EP1962115A9 (de) 2008-11-26

Family

ID=34069264

Family Applications (11)

Application Number Title Priority Date Filing Date
EP08005193A Withdrawn EP1962117A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005184A Withdrawn EP1956399A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005188A Withdrawn EP1980880A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005185A Withdrawn EP1980879A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP04019510A Expired - Lifetime EP1508822B1 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005192A Withdrawn EP1962116A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005190A Withdrawn EP1962114A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005191A Withdrawn EP1962115A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005187A Withdrawn EP1962112A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005189A Withdrawn EP1962113A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005186A Withdrawn EP1956400A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument

Family Applications Before (7)

Application Number Title Priority Date Filing Date
EP08005193A Withdrawn EP1962117A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005184A Withdrawn EP1956399A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005188A Withdrawn EP1980880A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005185A Withdrawn EP1980879A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP04019510A Expired - Lifetime EP1508822B1 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005192A Withdrawn EP1962116A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005190A Withdrawn EP1962114A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument

Family Applications After (3)

Application Number Title Priority Date Filing Date
EP08005187A Withdrawn EP1962112A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005189A Withdrawn EP1962113A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
EP08005186A Withdrawn EP1956400A3 (de) 2003-08-22 2004-08-17 Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument

Country Status (4)

Country Link
US (9) US7193780B2 (de)
EP (11) EP1962117A3 (de)
CN (1) CN1282882C (de)
DE (1) DE602004014687D1 (de)

Families Citing this family (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4331546B2 (ja) * 2003-03-26 2009-09-16 オリンパス株式会社 光学フィルタ及び光学機器
JP4409244B2 (ja) * 2003-10-14 2010-02-03 オリンパス株式会社 光学フィルタ及び光学機器
US7620586B2 (en) 2004-09-08 2009-11-17 Rosenthal Collins Group, Llc Method and system for providing automatic execution of trading strategies for electronic trading
US7940309B2 (en) * 2004-09-17 2011-05-10 Nikon Corporation Optical low pass filter and image-capturing device
EP1701395B1 (de) * 2005-03-11 2012-09-12 Novaled AG Transparentes lichtemittierendes Bauelement
JP2006317678A (ja) * 2005-05-12 2006-11-24 Olympus Corp 光学フィルタ及び光学機器
DE502005009415D1 (de) * 2005-05-27 2010-05-27 Novaled Ag Transparente organische Leuchtdiode
US7903338B1 (en) * 2006-07-08 2011-03-08 Cirrex Systems Llc Method and system for managing light at an optical interface
EP1895608A3 (de) * 2006-09-04 2011-01-05 Novaled AG Organisches lichtemittierendes Bauteil und Verfahren zum Herstellen
CN101047463B (zh) * 2006-10-25 2012-05-23 浙江大学 基于两端厚度递减结构的多通道波长空间解复用薄膜器件
DE102009026449B4 (de) * 2009-05-25 2014-04-30 Universität Kassel Optische Dünnschichtstruktur mit einer verteilten Kavität
US9588266B2 (en) 2011-05-17 2017-03-07 Canon Denshi Kabushiki Kaisha Optical filter and optical apparatus
JP2013031054A (ja) * 2011-07-29 2013-02-07 Ricoh Co Ltd 撮像装置及びこれを備えた物体検出装置、並びに、光学フィルタ及びその製造方法
EP2769250B1 (de) 2011-10-20 2021-12-01 3M Innovative Properties Company Apodisierte partielle breitband -reflektoren mit unterschiedlichen optischen paketen
CN104136946B (zh) * 2012-02-29 2017-03-08 柯尼卡美能达株式会社 近红外反射膜及使用其的近红外反射玻璃
CN103217730B (zh) * 2013-04-18 2015-07-08 同济大学 一种渐变光学厚度窄带负滤光片膜系
CN103472514A (zh) * 2013-09-26 2013-12-25 沈阳仪表科学研究院有限公司 一种类皱褶膜系结构的陷波滤光片
US9851571B1 (en) 2016-07-28 2017-12-26 Coherent, Inc. Apparatus for generating a line-beam from a diode-laser array
CN107132604B (zh) * 2017-06-26 2020-01-14 中国工程物理研究院激光聚变研究中心 渐变折射率薄膜制备参数获取方法、制备方法及滤光片
US11314004B2 (en) * 2019-04-08 2022-04-26 Visera Technologies Company Limited Optical filters and methods for forming the same
CN114690277B (zh) * 2020-12-28 2024-04-02 上海中航光电子有限公司 镀膜衬底及显示系统
CN112649903B (zh) 2020-12-28 2022-07-01 厦门天马微电子有限公司 复合膜组及其制备方法、采光装置和显示装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0967496A2 (de) 1998-06-22 1999-12-29 Alps Electric Co., Ltd. Optisches Mehrschicht-Filter

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6119962A (ja) 1984-07-06 1986-01-28 Toyota Motor Corp 燃料蒸発ガスのパ−ジ制御装置
US5056099A (en) * 1990-09-10 1991-10-08 General Dynamics Corp., Electronics Division Rugate filter on diode laser for temperature stabilized emission wavelength
US5291332A (en) * 1992-03-25 1994-03-01 Hughes Aircraft Company Etalons with dispersive coatings
US5928713A (en) * 1994-09-22 1999-07-27 United States Of America As Represented By The Secretary Of The Air Force Method for fabricating a gradient refractive index optical filter
US5828489A (en) 1996-04-12 1998-10-27 Rockwell International Corporation Narrow wavelength polarizing beamsplitter
JP2002333519A (ja) 2001-05-09 2002-11-22 Alps Electric Co Ltd 光学フィルタ
JP2003299226A (ja) 2002-04-01 2003-10-17 Sumitomo Wiring Syst Ltd 電気接続箱
JP4083456B2 (ja) 2002-04-02 2008-04-30 矢崎総業株式会社 箱体の固定構造
JP2003299224A (ja) 2003-04-24 2003-10-17 Mirai Ind Co Ltd 配線用ボックス
DE502005009415D1 (de) * 2005-05-27 2010-05-27 Novaled Ag Transparente organische Leuchtdiode

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0967496A2 (de) 1998-06-22 1999-12-29 Alps Electric Co., Ltd. Optisches Mehrschicht-Filter

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
RAHMLOW T D JR ET AL.: "Rugate and discrete hybrid filter designs", PROCEEDINGS OF THE SPIE - THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING SPIE-INT. SOC. OPT. ENG USA, vol. 3133, 1997, pages 25 - 35
SOUTHWELL W H: "Using Apodization Functions to Reduce Sidelobes in Rugate Filters", APPLIED OPTICS, OPTICAL SOCIETY OF AMERICA, WASHINGTON, vol. 28, no. 23, 1 December 1989 (1989-12-01), pages 5091 - 5094
TANG QI ET AL.: "JOURNAL OF VACUUM SCIENCE AND TECHONLOGY A. VACUUM, SURFACES AND FILMS", vol. 16, November 1998, AMERICAN INSTITUTE OF PHYSICS, article "Fabrication and characteristics of rugate filters deposited by the TSH reactive sputtering method", pages: 3384 - 3388
WANG X ET AL.: "JOURNAL OF VACUUM SCIENCE AND TECHNOLOGY A. VACUUM, SURFACES AND FILMS", vol. 17, January 1999, AMERICAN INSTITUTE OF PHYSICS, article "Design and experimental approach or optical reflection filters with graded refractive index profiles", pages: 206 - 211

Also Published As

Publication number Publication date
EP1962114A3 (de) 2008-09-03
EP1508822A2 (de) 2005-02-23
EP1962113A2 (de) 2008-08-27
US7271959B2 (en) 2007-09-18
EP1962114A9 (de) 2008-12-10
EP1980879A2 (de) 2008-10-15
US20070103785A1 (en) 2007-05-10
US7369314B2 (en) 2008-05-06
US20070103784A1 (en) 2007-05-10
EP1962112A2 (de) 2008-08-27
EP1980879A3 (de) 2008-10-29
EP1962112A3 (de) 2008-09-03
EP1962117A3 (de) 2008-09-03
US7265905B2 (en) 2007-09-04
US7324283B2 (en) 2008-01-29
EP1962116A3 (de) 2008-09-03
EP1962114A2 (de) 2008-08-27
EP1962113A9 (de) 2008-11-26
EP1962115A3 (de) 2008-09-03
US20070109648A1 (en) 2007-05-17
US20070109645A1 (en) 2007-05-17
US20070263287A1 (en) 2007-11-15
DE602004014687D1 (de) 2008-08-14
EP1956400A3 (de) 2008-09-03
US7289268B2 (en) 2007-10-30
EP1962117A2 (de) 2008-08-27
EP1956399A3 (de) 2008-09-03
EP1962117A9 (de) 2008-12-10
EP1508822A3 (de) 2005-05-25
EP1508822B1 (de) 2008-07-02
CN1584635A (zh) 2005-02-23
EP1980880A3 (de) 2008-10-29
EP1962113A3 (de) 2008-09-03
US7274512B2 (en) 2007-09-25
CN1282882C (zh) 2006-11-01
EP1980880A2 (de) 2008-10-15
EP1962112A9 (de) 2008-11-26
EP1962116A2 (de) 2008-08-27
US20070109647A1 (en) 2007-05-17
EP1956399A2 (de) 2008-08-13
US20050041293A1 (en) 2005-02-24
US20070109646A1 (en) 2007-05-17
US7193780B2 (en) 2007-03-20
US7312925B2 (en) 2007-12-25
EP1962115A9 (de) 2008-11-26
US20070095958A1 (en) 2007-05-03
EP1956400A2 (de) 2008-08-13
US7277228B2 (en) 2007-10-02

Similar Documents

Publication Publication Date Title
EP1508822B1 (de) Optische mehrschichtige Filter mit periodischer Variation des hohen und niedrigen optischen Brechungsindex und optisches Instrument
WO2004106995A1 (ja) 光線カットフィルタ
EP1607772B1 (de) Optisches filter und optische vorrichtung
JP6795365B2 (ja) ズーム対物レンズ
CN117891012A (zh) 光学元件
DE10249702A1 (de) Zoomsystem
JP4409244B2 (ja) 光学フィルタ及び光学機器
JP4343620B2 (ja) 光学フィルタ及び光学機器
US20080030858A1 (en) Optical filter and optical apparatus
JP4331547B2 (ja) 光学フィルタ及び光学機器
JP4608585B2 (ja) 光学フィルタ及び光学機器
CN100390576C (zh) 光学滤波器及光学设备

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

PUAL Search report despatched

Free format text: ORIGINAL CODE: 0009013

17P Request for examination filed

Effective date: 20080319

AC Divisional application: reference to earlier application

Ref document number: 1508822

Country of ref document: EP

Kind code of ref document: P

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

AK Designated contracting states

Kind code of ref document: A3

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR

AX Request for extension of the european patent

Extension state: AL HR LT LV MK

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: OLYMPUS CORPORATION

17Q First examination report despatched

Effective date: 20081113

AKX Designation fees paid

Designated state(s): DE FR GB

REG Reference to a national code

Ref country code: HK

Ref legal event code: DE

Ref document number: 1124125

Country of ref document: HK

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20100302

REG Reference to a national code

Ref country code: HK

Ref legal event code: WD

Ref document number: 1124125

Country of ref document: HK